题目内容：

Football is a popular sport. More than a million kids play on high school teams, but football can be a hazard. The National Football League(NFL) has acknowledged that almost 30 percent of its players will eventually suffer from brain-related diseases. That’s a lot.

A recent study involving 40 former NFL players showed that those who started playing football before age 12 did worse on thinking tests than players who started after age 12. By the way, all the tested players scored below average for their age and education. Concerns about the effects of constant hits to the head have caused some medical experts on brain injuries, such as Robert Cantu of Boston University, to recommend that kids not play football before age 14.

I don’t think football is all bad. It helps kids learn teamwork, discipline and how to get into better physical condition. But now that we know that the sport might be dangerous, it’s time to make some changes in the youth and high school football.

First, seasons should be shorter. The high school regular season should not be more than nine games. Second, kids should not play tackle(擒抱) football too soon. As Cantu points out, “By age fourteen, our necks are strong and our overall body strength is sufficient to keep the head steady when we slam at the line of scrimmage(争球).” Personally speaking, I don’t think kids should sit on the couch until they are 14. But they can play flag football and other gentler sports. If you think age 14 is too late to become a good football player, remember that four-time Super Bowl winner Tom Brady started playing football at that age.

1.What does the underline word “hazard” mean?

A. difficulty.    B. danger.

C. punishment.    D. pain.

2.Why did the former NFL players perform badly in tests?

A. Their heads were hit frequently.

B. They had some mental disorders.

C. They didn’t take the tests seriously.

D. They received little school education.

3.What does the author advise for kids under 14?

A. They watch football games.    B. They play safer games.

C. Football be forbidden for them.    D. They play 10 games a season.

4.What is the purpose of the text?

A. To entertain.    B. To advertise.

C. To instruct.    D. To warn.